Toothbrush



FIG. 1 is a bottom plan view of a toothbrush embodying our new design;

FIG. 2 is a left side elevation thereof; the right side elevation is a mirror image of the left side elevation as shown herein in FIG. 2; and,

FIG. 3 is a top plan view thereof. 

The ornamental design for a toothbrush, as shown and described. 